Abnormal fuel injection system of Bare Engine leads to bent or broken connecting rods

This situation is usually caused by continuous fuel injection from a cylinder injector of an MG Roewe Maxus Engine. Often, there will be difficulties starting, idle shaking, black smoke from the exhaust pipe, and decreased power before.

After disassembly and inspection, it can be determined by observing the combustion condition of each cylinder. Due to the richer combustible mixture compared to other cylinders, the cylinder and cylinder head will be darker than other cylinders. At the same time, the fuel injector and its injection control circuit can be further inspected.

Bare Engine may bend or break due to the locking of connecting rods and crankshafts. This situation is usually caused by poor lubrication of Bare Engine and can be judged by checking the wear of internal parts of Bare Engine.

The problem with the connecting rod itself leads to bending or breakage. This situation can generally be determined by analyzing the chemical composition of the connecting rod material, hardness testing, metallographic structure testing, and fracture analysis using scanning electron microscopy.

The possible reason is that quenching microcracks lead to low stress fatigue fracture, resulting in a decrease in the mechanical properties and fatigue life of the connecting rod, including pearlite+flakes, oversized non-metallic inclusions, blocky ferrite, etc.